Construction of the Large Scale Activation Tagging Lines and Characterization of a Lesion Mimic Mutant

Abstract

Activation tagging system using a T-DNA vector that contains tetramer of the 35S enhancer followed by its minimum promoter was applied to rice. We have produced approximately 8,000 lines. Among them, one lesion mimic, eight stripe, and one needle-like leaved mutants were obtained in the T0 generation.
The lesion mimic mutant, which was dominant, was further characterized. The phenotype was linked to the T-DNA in the T1 generation. The genomic DNA adjacent to the T-DNA was cloned and sequenced. An open reading frame was located about 500 bp downstream of the T-DNA and the lesion mimic phenotype correlated with the enhanced expression of the mRNA in the T1 generation. The encoded protein shows sequence similarity to a protein whose expression is induced by hypersensitive reaction in tobacco. We are now investigating to confirm whether the overexpression of the gene is sufficient to induces the lesion mimic phenotype.